Rotaviruses are consistently shown to be the single most important cause of severe diarrhea of infants and young children in both developed and developing countries. The consequences of rotavirus diarrhea are staggering as they account for up to 592,000 deaths annually in the under 5-year age group, predominantly in the developing countries (Parashar et al, Emerg. Infect. Dis., 2003, 9:565-572). It has recently been estimated that 1 in 200 children in developing countries will die from rotavirus diarrhea (Glass et al, Lancet, 2004, 363:1547-1550). In the United States, in the under 5-year age group, it was estimated that annually rotaviruses are responsible for 2,730,000 episodes of diarrheal illness, 410,000 visits, to a physician, 160,000 emergency room visits, 50,000 hospitalizations, and 20 deaths (Tucker et al., JAMA, 1998, 279:1371-1376). Thus, the need for a rotavirus vaccine in both developed and developing countries has received national and international endorsement.
WO2007009081 had proposed the use of a hexavalent bovine rotavirus (UK)-based vaccine for developing countries to cover not only the standard serotypes G1 through G4 but also emerging serotypes G8 and G9.
Development of Hexavalent Rotavirus vaccine comprising of standard G1-G4 strains and G9, G8 strains for a broader degree of protection has been previously discussed see Albert Z. Kapikian et. al. “A Hexavalent human Rotavirus-bovine Rotavirus reassortant vaccine designed for use in developing countries”; National Institutes of Health; Journal of infectious diseases; 2005; 192; S22-9 Rotavirus strains may lose viability during drying process and storage. It has been reported previously that lyophilization causes upto 30% loss in virus potency.
Protein formulations containing sucrose-glycine combination have been described by Wei Liu et. al. “Freeze drying of Proteins from a sucrose-glycine excepient system: Effect of formulation composition on initial recovery of protein activity”; AAPS Pharm Scitech; Feb. 11, 2005; 6(2); E150-E157
A lyophilized rotavirus vaccine formulation according to U.S. Pat. No. 6,616,931, U.S. Pat. No. 6,403,098 & U.S. Pat. No. 5,932,223 comprising a strain of rotavirus about 1×105 to about 1000×105 pfu/mL, a sugar 1-20% (w/v), Phosphate about 0.05-2 M and a) 0.5%-1.25% of recombinant human serum albumin or b) 0.1%-1.25% of an amino acid (glutamate, glutamine or arginine). Further the patents also discuss improved stability of lyophilized rotavirus formulation by including glycine (1%) in the sucrose/mannitol stabilizer.
There remains a distinct need for rotavirus vaccine formulations with improved viability and stability. None of the prior art stabilizers improve viability & stability. Further for worldwide distribution of rotavirus vaccines, it is necessary to formulate vaccines such that they are stable under a variety of environmental conditions.
Surprisingly, it has now been discovered that a) stabilizer composition comprising of combination of Sucrose and Glycine and b) optimal lyophilization cycle results in a Rotavirus formulation with a moisture content less than 3% and 100% individual virus preservation.